Non-linear ranging to control linear ranging measurement device

摘要

A range selection circuit (13), including a logarithmic amplifier (23) and output circuitry (25) associated therewith, is configured to directly drive linear ranging circuitry for measurement circuitry (12) in an optical power meter (10) to measure signals that vary over a wide range of, for example, from about -7dB to about -45dB. This allows the optical power meter to change ranges as fast as one (1) times the hardware settling time. The range selection circuitry is in parallel with the measurement circuitry, which allows ranging to happen in real time.